<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link rel="stylesheet" href="css/flex.css">
</head>
<body>
    <div class="container">
        <div class="item">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
        <div class="item">6</div>
        <div class="item">7</div>
        <div class="item">8</div>
    </div>
    <h2>子元素设置</h2>
    <div class="container1">
            <div class="item1">1</div>
            <div class="item1">2</div>
            <div class="item1">3</div>
            <div class="item1">4</div>
            <!-- <div class="item1">5</div>
            <div class="item1">6</div>
            <div class="item1">7</div>
            <div class="item1">8</div> -->
        </div>
    <div class="contaier3">
        <div class="box"></div>
    </div>
    <hr>
    <div class="big">
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
        <div class="small"></div>
    </div>
</body>
</html>